Extract `getNotification` from `removeNotification`
Extract `getNotification` from `removeNotification`

And optimize `getNotification` to stop iterating once a
notification matching the given `uid` is found.

batmandarkside/react-notification-system-2,igorprado/react-notification-system,batmandarkside/react-notification-system-2,igorprado/react-notification-system